When I want to Draw I am not moving the pen as fast as when I am writing. Even when I am moving the pen (slowly) it still thinks that I am holding it still and erases the line, which is very annoying.
Try to move the pen slowly over the screen - sometimes it even makes a dashed line. It does not do this with the ipdf from iRex.
Using the 2.21.1 version on a iRex iLiad Book edition